The proposed research is designed to further characterize selected membrane properties of normal and chronic lymphocytic leukemia (CLL) lymphocytes. Two areas will be investigated: (1) The mechanism and biologic consequences of the decrease in 5'nucleotidase (5'N) in CLL lymphocytes will be evaluated as follows: a. Experiments are planned to determine whether the exfoliation of plasma membrane with shedding of enzyme by CLL lymphocytes or a decrease in synthesis account for the decrease in 5'N. b. Experimental approaches are planned to study the effect of 5'N on the endogenous nucleotide pools and determine whether multiple 5' nucleotidases occur. c. The relationship of 5'N to immunoglobulin synthesis will be clarified. d. Attempts will be made to separate the 5'N+ and 5'N- subpopulations and compare their biologic properties. (2) The anomalous capping behavior of CLL lymphocytes will be investigated as to a possible role played by defects in contractile proteins, energy availability and lipid abnormalities. The results of these experiments may serve to clarify the function of 5'N in the regulation of nucleotide metabolism and the immune response. The studies of capping will test several hypotheses to account for the impairment in this potentially important function in CLL lymphocytes.